Red Deer River Basin - Water Supply Forecasts

Recorded March to September 2008 natural runoff volume in the Red Deer River basin was much above average at Dickson Dam, and above to much above average at the city of Red Deer. Natural volume forecasts produced for the Red Deer River basin were within 33.7% of recorded values, on average (Table 1).

Due mainly to two major storms in May and June, March - September 2008 natural runoff volumes into Glennifer Lake and at Red Deer were 15th and 22nd highest in 91 years of record, respectively.

The six monthly (February to August, excluding June) forecasts of March through September 2008 natural volumes produced for the Red Deer River basin were within 11.4% of recorded values, on average. No forecasts were produced in June this year due to flood events. Volumes were underestimated in the first four forecasts due to major storms in May and June that radically increased runoff volumes, as the upper quartile forecasts were exceeded. July and August forecasts were high, as the recorded volume was less than the lower quartile forecasts, and less than August's minimum forecast at Red Deer.

Natural runoff volumes measured during the month of September were above average at both the Dickson Dam and at Red Deer (Table 1).

Red Deer River at Dickson Dam

The March to September 2008 recorded natural volume for the Red Deer River at Dickson Dam was much above average at 1,283,600 dam³ or 137% of average, and ranks 77th lowest (15th highest) on record (based on the 1912-2001 data) (Table 1).

Six monthly (February to August, excluding June) natural volume forecasts were produced for Dickson Dam for the March to September 2008 period. Volumes were underestimated in the first four forecasts due to major storms in May and June that radically increased runoff volumes, as the upper quartile forecasts were exceeded. July and August forecasts were high, as the recorded volume tracked closer to the lower quartile forecasts these two months.

Forecasts ranged within 47.9% to 51.0% of the recorded volumes for the first four monthly forecasts, and 5.8% to 13.7% for July and August's forecasts.

Red Deer River at Red Deer

The March to September 2008 recorded natural volume for the Red Deer River at Red Deer was above to much above average at 1,617,200 dam³ or 124% of average, and ranks 70th lowest (22nd highest) on record (based on the 1912-2001 data) (Table 1).

Six monthly (February to August, excluding June) natural volume forecasts were produced for Red Deer for the March to September 2008 period. Volumes were underestimated in the first four forecasts due to major storms in May and June that radically increased runoff volumes, as the upper quartile forecasts were exceeded. July and August forecasts were high, as the recorded volume was less than the lower quartile forecasts, and less than August's minimum forecast.

Forecasts ranged within 38.3% to 42.6% of the recorded volumes for the first four monthly forecasts, and 8.4% to 10.6% for July and August's forecasts.